Slide fastener



W. W. ENGLlSH SLIDE FASTENER June 30, 1953 Filed May 6, 1950 W@ @i I f" Figure 5a Figure 1ra Figure 5 b LCE@ Figure 1 Figure 3 Figure 33 t Figure 3b TTO/Q/VEY Patented June 30, 1953 UNITED STATES PATENT OFFICE SLIDE FASTENER William W. English, Westport, Conn.

Application May 6, 1950, Serial No. 160,513

2 Claims. l

This invention relates to separable fasteners of the type generally known as slide fasteners,

and is composed of a plurality of stringers which are. attachable to parts to be joined and a slider adapted to embrace the stringers in such a manner that, in being moved progressively along the length of the fastener, the slider causes the stringers to come into suitable position in relation to each other for interengagement or disengagement.

In one embodiment the stringers comprise coils or helices. vIn another embodiment the stringers are formed by stamping from a flat sheet` material such as plastic which is then rolled to form a cylindrical piece with locking elements constituting parts Vof helices.

An object of the invention is to provide novel and improved slide fasteners of the type above described.

Various other objects and advantages will be apparent from the following description, taken in connection with the accompanying drawings in which certain specic embodiments are set forth for purposes of illustration.

In the drawings:

Fig. 1 is a fragmentary front elevation, partly in section, illustrating one embodiment of my invention;

Fig. 2 is an enlarged and partly sectional view of a. slightly modified form of the same invention;

Figs. Band 4 are plan Views of a portion of I'latl blanks stamped to form cooperating stringers;

Fig. 5 is a detail View showing apair of string.

wound in the same direction as coil a, and at-v i tached to the same material or tape f at points equidistant or ,approximately equidistant betweenV points where coil a is attached to tape f. Coils a and b together with the tape f which carries them make up one stringer. Coil c is a helical coil wound in opposite direction Vto coils a and b and having a pitchhalf that of either coil a or coil b. Coil c is attached to its tape fby suitable means g, and the coil c and its tape to-l l gether comprise a second stringer.

Coil c is wound in such ya manner that the interspaces between turns or convolutions are less than, are equal to, or are not greatly more than the ydiameter` or width of the stock or filament from which coils a an-d b are wound. Since coils a and b each have a pitch twice that of coil c, a not necessarily identical but similar and constantrelationship exists regarding the interspace between a given turn of coil a and an adjacent turn of coil bn as compared with the diameter or width or stock from which coil c is wound.

A conventional slider d is used, the slider d having, an opening at the lower end large enough to carry coil members of both stringers in en-V only, and the two openings `diverging at such an angle as to permit the interspaces between coil turns to be greater where the stringers meet than those interspaces are when stringers lie parallel to each other in engaged position, The slider al` has also, of course, a slot on either side, running the lengthof the slider, to permit pas? sage of tapes f, f.

In Fig. 2, coil elements like those shown in Fig. 1 bear like reference characters. The coils in Fig. 2 are shown as having been made of stock having across section diiierent from that of the stock from which coils shown in Fig. 1 are made. The cross section of any coil filament at any point is immaterial so long as the basic principle of using acoil or coils of opposite winding direction and diierent pitches on the two stringers is adhered to.

Also in Fig. 2 a turn of coil c passes between a turn of coil a and a turn of coil b, making contact at points :i and 1c. The line 77s between points j and lc can be seen to be out of parallel with the edge-e of tape f, both in a front-to-rear direction and in a left-to-right direction. (Edge e of tape j will hereinafter be considered and called vertical, for convenience in description.) Therefore, a segment or turn of coil c can pass between adjacent segments of coils a and b through an interspace which, measured vertically, would be less than the vertical dimension of a vertical cross section of a segment of coil c. `The more nearly the cross section of the coil-l stock approaches circular inshape, the less dif.-y

even if interspace dimensions are allowed to equal or even to appreciably exceed the vertical dimension of the coil-stock passing through the interspaces, the fastener can still function efficiently, as will presently be shown. Still referring to Fig. 2, two coil segments cc and ccl are shown as though separated from their complete coil c. These segments are shown in the positions they assume when the stringers are interengaged. Segment bb of coil b is also shown in its normal position when stringers are interengaged. Any lateral pull intended to disengage the two stringers must, to be effective, cause segment bb to pass between segments cc and ccl. It can be seen in Fig. 2 that it is not possible to pass segment bb between segments cc and cci without increasing the vertical interspace between segments cc and ccl and/or without changing the pitch of segment bb to conform with the pitch of segments cc and ccl and/or vice versa. Thus, when effective vertical interspaces are less than the vertical dimension of a vertical cross section of ia coil segment passing through one of the interspaces, disengagement in a lateral direction cannot be effected because the coils a, b, c, being individually attached to tapes f, f, are prevented from expanding vertically or longitudinally. Also, regardless of any precise relation between interspace dimension and dimension of coil segment cross section, disengagement cannot be effected unless enough lateral force be applied to distort the pitch or coil turns on one Stringer to an extent that will match the concurrently distorted pitch of coil turns on the other Stringer at points of contact.

In the example shown in Fig. 2, even if average vertical interspace dimensions were as great as average vertical cross-section dimension of coil stock, each turn of coils a and b would have to be distorted by force until the pitch of-each turn of coils a and b at points of contact with turns of coil c was reduced to approximately threefourths the normal pitch of coils a. and b at rest, and the pitch of each turn of coil c at points of contact with adjacent turns of coils a and b would have to be increased to approximately one and one-half times the normal pitch of coil c at rest, before disengagement could be effected in a lateral direction.

In the example shown in Fig. 2, two coils are used on one Stringer, each coil having twice the pitch of the single coil used on the other stringer. lIt is the use of coils of different pitch which is the important functional feature of this invention rather than the precise number of coils used on either, any or all stringers.

In Fig. 2, h, l1. represents part of a series of appropriately spaced openings in tape f, through which openings any of the various coils might be laced or threaded in the manner of a screw.

Figs. 3 to 5b, inclusive, disclose an improved method of manufacturing slide fasteners embodying the principle of using coils of different pitch.

Figs. 3 and 3a show a portion of a strip of cast or sheet stock having edge flanges p, p turned at an angle to the general width of the strip. `Slots m, m, m are stamped through or otherwise formed across a portion of the width of the strip, leaving bands b, a, b, which lie at an angle to a vertical line as dened by a longer edge of surface p.

Figs. 4 and 4a show a portion of a similarly formed strip, but having slots n, n, n cut through and bands c, c, c remaining. Bands c, c, c in Fig. 4 slope downward in a direction opposite to that 4 taken by bands b, a, b in Fig. 3 and lie at an angle to the vertical which is different from the angle at which bands b, a, b, in Fig. 3 would meet a vertical line.

The two slotted strips represented in Figs. 3 and 4 are rolled or curled about a longitudinal axis until the two surfaces p, p meet or approach each other, thus producing, as shown in Figs. 5 and 5a, a result which is, in effect and in function, the same combination of coils of different pitches as has been previously shown in Figs. 1 and 2.

The rolled forms as shown in Figs. 5 and 5a can be attached to tapes f, f or directly to parts to be joined either adhesively or by suitable means such as stitching g. The flanges as seen in Fig. 5 need not be continuous throughout the length of the fastener, but may be subdivided into a series of separate tabs, if desired.

A further simplification of this manufacturing and attaching procedure is shown in Figs. 3b and 5b. Fig. 3b is a section of `a strip similar in appearance and in slotting to the strip shown in Fig. 3, but without the edge anges or surfaces p, p. In Fig. 3b, s indicates the side edges of the strip. This strip is rolled into cylindrical form about a longitudinal axis, allowing edges s, s, to meet or approach each other. The result is in effect and in function a complete Stringer. The tape f or the actual material of one of the parts to be joined is inserted between the now juxtaposed edges of the rolled strip as shown in Fig. 5b. The slots or interspaces and bands or coil segments are held in proper relationship to one another by the unslotted portions t, t.

For positive gripping action on the tape or material f, the side edges s, s may be serrated or the rolled form may be attached to material J adhesively or by stitching through the slots.

The advantages in making slide fastener stringers in this manner are many, including the following:

The necessity for employing a tape to prohibit lengthwise expansion of stringers is eliminated.

In Suitable cases, the Stringer member may be formed directly on and of a portion of the material of one of the parts to be joined.

Due to the fact that incomplete convolutions are used, any given approximate coil segment need not necessarily be placed so that a continuation of that coil segment would coincide with the position of the next or any other coil segment on the Stringer. Thus a greater variety of pitch combinations is available, toward attainment of maximum resistance to disengagement of intermeshed stringers.

The pitch of one edge of any coil segment may differ from the pitch of the other edge of the same coil segment.

Any coil segment can be so formed that the pitch of either of its edges changes at any point on that edge.

Any coil segment can be so formed that either edge of the segment changes its direction, in the sense of winding-direction of a coil, at any point.

Any coil segment could be formed so that its pitch at any point would be reduced to zero. The edge surface of that segment at that point would correspond to the edge surface of a ring, and could be used in conjunction with pitched edge surface on a segment of an opposing Stringer to provide the resistance to disengagement hereinbefore described.

For convenience or for appearance, the circular cross sections as seen in Figs. 5a and 5b may be attened to elliptical shape or otherwise deformed Without departing from the basic concept.

Various other changes may be resorted to within the spirit and scope of the invention.

What is claimed is:

1. A slide fastener comprising a pair of stringers having interlocking portions, at least the interlocking portions of each Stringer having the form of segments of a helix, the segments of one stringer comprising a pair of interleaved members each having a pitch which is double that of the segments of the other Stringer, said interleaved members being spaced to receive a segment of said other Stringer between each pair of adjacent segments of said interleaved members whereby the segments of the respective stringers are distorted to parallel relationship and frictionally gripped for securing said stringers together.

2. A slide fastener comprising a pair of stringers, one Stringer comprising a single helical member, the other Stringer comprising members 6 forming a double helix, each of said last helices having double the pitch of said first helical member, said double helix members being spaced to receive a segment of said single helical member between each pair of segments of said double helix whereby the helices are distorted into parallel relationship and frictionally gripped to secure said stringers together. 1

WILLIAM W. ENGLISH. 

